Within the project area their is a strong interest in the culture of the African catfish if the response to the organized field days is regarded. The actual number of farmers which are rearing the African catfish is limited due to the fact that fingerling production really started this year and most of the fingerlings produced at Kibos are used by the other FPC's. No reliable data on the present status of catfish rearing by private farmers were available and therefore only general statements/recommendations can be given.
Mono culture of the African catfish can be done when suitable feed, with a high protein content (including animal protein) is available.
The stocking rate depends on the marketable size desired and varies from 2 to 10 fingerlings per square meter, corresponding to a marketable size fish of approximately 500 and 200 g respectively after 6 month. Higher stocking densities are not recommended as adverse water conditions at the end of the production cycle are difficult to manage.
Feeding with a balanced composed feed is a prerequisite for intensive mono culture of the African catfish. The feed should contain 30–35 percent digestible protein (about 40–50 percent crude protein) and 2500–3500 kcal digestible energy/kg feed (about 3500–4500 crude energy/kg feed). The feed is distributed two to three times a day in equal portions.
Some biological data on Mono culture of the African catfish is presented in Table 4.
| Week | Mean body weight (g) | Survival (%) | Biomass (kg/100 m2) | Feeding rate (%/biomass/day) | Feed4 (g/100 m2/day) |
| 0 | 1 | 100 | 1 | 10 | 100 |
| 2 | 5 | 70 | 3.5 | 7.5 | 250 |
| 4 | 10 | 65 | 6.5 | 4.5 | 300 |
| 6 | 18 | 60 | 10.8 | 4.0 | 400 |
| 8 | 27 | 60 | 10.2 | 3.3 | 525 |
| 10 | 36 | 60 | 21.6 | 3.0 | 650 |
| 12 | 52 | 55 | 28.6 | 2.7 | 775 |
| 14 | 65 | 55 | 35.7 | 2.6 | 900 |
| 16 | 79 | 55 | 43.4 | 2.4 | 1025 |
| 18 | 102 | 50 | 51.0 | 2.3 | 1150 |
| 20 | 130 | 50 | 65.0 | 2.1 | 1350 |
| 22 | 160 | 50 | 80.0 | 1.9 | 4500 |
| 24 | 200 | 50 | 100.0 | 1.8 | Harvest |
4 A higher feeding rate should be used if the feed has lower protein or caloric values.
Source: Janssen, 1987
After about six month the pond can be harvested and net production of 9–16 t/ha/year can be obtained.
The major problems of intensive monoculture of the African catfish are; water quality and predation
Overfeeding of the fish will result in adverse environmental conditions (low oxygen, high ammonia, high suspended solids, etc). Adverse water conditions often coincides with dense phytoplankton blooms followed by a scum of phytoplankton at the surface of the pond. This will cause low oxygen levels at night and pre-dawn. Flushing of the pond and reduction of the feeding level is the only remedy
Predation is another major problem in intensive farming of the African catfish and high predation can be expected by the predation through birds, especially at Kibos.
The privatization of the fingerling production of the African catfish will be feasible once the demand for fingerlings is established e.g. once large number of private farmers are rearing the catfish to market size. The extension of clarias farming in the project should follow the following sequences;
Show the profitability of the mono culture catfish to private farmers. This can be done through demonstration ponds. Care must be taken that risk are not placed at the farmers side as long as the technique of mono-culture is not metricized by the project technicians. Some failures/loss of money by private farmers will result in the fact that the farmers will lose their confidence in the project.
Fingerlings are produced by the FPC's in the project area and sold to the farmers and the extension officers will advice the farmers on all practical matters.
Private farmers are assisted/trained in the fingerling production and will gradually take over the role of the FPC's as fingerling producers.
There are several options for privatization of the fingerling production.
The private fingerling producers buys the 3 day old larvae from a specialized reproduction centre (FPC or private) and raise them till fingerlings in earthen ponds as described before. This is probably the easiest option as the involved farmers do not have to invest. The farmers are however dependant on an outside source for their stocking material. From a practical point of view the project can start this way with farmers which are interested in the production of fingerlings. Once the involved farmers metricize the technique and once they are making a reasonable profit, then they are keen to learn how to produce three day old larvae and they are willing to make investments for a small scale hatchery and a broodstock pond.
The nursing of the fingerling takes place in earthen ponds and the needed stocking
material is produced by the farmer in a small scale hatchery.
A production unit with a capacity of 100,000 fingerlings per year consists of;
The reproduction must be carried out artificially, through stripping as the farmer needs 70,000 fertilized eggs in order to produce the number of larvae required for the stocking of 1 nursery pond.
This private production unit can supply the fingerlings for 0.5 ha grow out ponds (10 fingerlings/m2, 2 cycles per year) and can further supply 3 day old larvae to other private nurseries.
5 More pond will do also, as long as the total remains at 400 m2.
There is a possibility that a private farmer wants or has to produce his own fingerlings for the grow out ponds. The number of fingerlings needed is rather low (1000 fingerlings/100 m2 grow out pond) and therefore the used methodology must be simple and cheap. During the training course we succeeded to reproduce the African catfish semi-artificial in a happa which was placed in a pond. The proposed technique, which has to be refined at Kibos, is described below;
The farmer must have a small broodstock pond (20 m2) where 10–20 breeders are kept, as the male catfish from his grow out ponds won't be mature after 6 month.
A happa of 2 m2 is made of mosquito netting (mesh size 1 mm, investments 300 Shilling) and placed in a pond which is just filled and fertilized.
A “ripe” female (300–500 gram) is injected with a Nile perch pituitary and placed together with a male in the happa. The pituitary of Nile perch is obtained from a fresh carcass of a medium sized nile perch or is sold by the project or private entrepreneurs.
Spawning takes place in the night after injection and the following morning the breeders are removed from the happa and returned to the broodstock pond.
The fertilized eggs are kept in the happa where they will hatch and after 3–4 day the developed larvae are released into the pond.
The released larvae are raised to fingerlings following the common procedures and harvested and graded after 3–4 weeks and the medium sized fingerlings are returned to the same pond. Harvesting and grading after 3–4 weeks will be the most critical factor. The farmer will be reluctant to drain off a nice fertilized pond but this is essential as the stocking density is low and cannibalism will appear quickly. The farmer will end up with a couple of very large fingerlings if this procedure is not carried out properly.
